Prince Caspian
Main Outfit

Caspian leaves Miraz's castle in this outfit, and wears it right
up until the duel, where he changes out of the shirt and adds
Narnian armor with his brigandine.

The two main parts of his main outfit are his beautifully embroidered
shirt and his brigandine, both of which have study pages of their
own. All the images of the main outfit are on this current page,
while the images from this page that best show the shirt or brigandine
are on their respective pages.

Trousers

His trousers button down the sides to about the knee, with a
row of diamond-shape embroidery on at least one side. While it
looked like it might be lacing at first, one can see the buttons
and embroidery clearly from the images here. The first has the
buttons pointed out, and the second is a copy of two stills from
this point on the trailer—one
can just spot Caspian riding off to the left after a night raid
on Miraz's castle.

There's a particularly good shot of this in the movie storybook,
in the Peter-Caspian fighting shot.

Cloak and Gloves

On his night journey fleeing Miraz's castle, he wears
a dark purple/blue, almost plum colored cloak. Stansborough confirms
that this is a wool, a felt. It has a hood with seam shaping.
It attaches to itself with a string at the front, gapping about
six inches. His riding gloves are a dark brown color.

Sword and Accessories

The side-sword he carries in most images does not seem to be
the one we see in the photoshopped teaser poster: that sword looks
more like a combination of the gold crossguard and rings of Miraz's
sword (Caspian is holding Miraz's sword here
and here), with Caspian's sword hilt.
Caspian's sword has slightly different styled rings, plus the
hilt and crossguard are silver.

His sheath and sword hang at his left side from a tooled leather
baldric (the shoulder belt). Over the baldric is his belt, holding
his dagger sheath at his right side. He carries Susan's horn.

At Aslan's How and on the night raid he wears brown leather
vambraces.